OK, I'm getting tired of this hand-waving, so I made some quick modifications to my old endurance calculator so that it could handle some simple examples from 2e.
I used the following stats, from memory:
- Chipped Greataxe (Berserker starting weapon): blue+red dice, S: +1 damage, S: +1 damae
- Reaper's Scythe (Necromancer starting weaon): blue+yellow dice, S: +1 range
- Cave Spider (minion): 3 health, 1 gray defense die
- Cave Spider (master): 5 health, 1 gray defense die
- Shadow Dragon (master): 9 health, 2 gray defense dice, "Shadow" (in 1e terms, this is Fear 1, but only against adjacent attackers)
Those weapons were chosen because they didn't require me to rewrite my macros to limit surge abilities to once-per-attack (the greataxe can't roll more than 2 surges, and the scythe's surge ability is irrelevant because I assumed close-range attacks) - also, they're the strongest and weakest weapons I remember the stats for. I used this preview article to determine what the dice can roll. And just to be clear, all of these stats include the chance of missing due to rolling an X on the blue die, and do not include bonuses from skills.
Based on those stats, here's the average number of attacks the Berserker needs to kill things:
- Cave Spider (minion): 1.4 attacks (~2/3 chance to one-shot)
- Cave Spider (master): 2.1 attacks
- Entire group of cave spiders (4 minions + 1 master): 7.6 attacks
- Shadow Dragon (master): 9.5 attacks
And the Necromancer, assuming he stay close enough that there's no missing due to range, needs an average of:
- Cave Spider (minion): 2.2 attacks (~1/4 chance to one-shot)
- Cave Spider (master): 3.5 attacks
- Entire group of cave spiders (4 minions + 1 master): 12.5 attacks
- Shadow Dragon (master), from 2 spaces away: 9.2 attacks
- Shadow Dragon (master), from 1 space away: 13.9 attacks
Based on these numbers, killing a master shadow dragon in one round would be unusual, and a melee-heavy party can probably expect that it will take longer than an entire group of cave spiders. Remember that I'm using the group size for 4 heroes, which means the dragon group will also contain a minion, in addition to that one master - that's not represented here, because I don't remember its stats.
I don't know the stats for ettins. If anyone's got them, I can run those numbers, too.